Adrenoleukodystrophy (ALD) and adrenomyeloneuropathy (AMN) are serious progressive disorders of the nervous system and are also associated with adrenal insufficiency. Both disorders are x-linked, but ALD occurs at an earlier age and causes more rapid and severe symptoms. Both disorders show characteristic cytoplasmic inclusions and the accumulation of very long-chain fatty acids (C26-C30) in the nervous system white matter and adrenal cortex. The basic biochemical defect is unknown. We have recently shown that cultured skin fibroblasts from ALD or AMN patients have an abnormally high ratio of C26 to C22 fatty acids. Pilot data indicate that this ratio may also be increased in women who are obligate heterozygotes for ALD or AMN. We propose to determine if further refinement of this technique, such as the use of cloned cell populations can achieve reliable identification of the ALD heterozygote. We also will study the fatty acid composition of cultured amniotic fluid cells in order to explore the possibility for prenatal diagnosis of ALD or AMN.